Alternating-current magnet.



w. D. L'UTZ.

AL-TERNATING CURRENT MAGNET.

APPUCATION FILED JULY 31.19l3.

1,166,699, Patented Jan. 4-, 195 5.

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WITNESSES: max m/a v 7 b2 WX/TLZ h f {#5 2 Z I" l 05/, ATTO NEWlLl'lhlTTED STATES PATENT OFFICE.

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I), LUTZ, OF ALLENLDALE, NEW JERSEY, ASSIGNOR TO OTIS ELEVATOR .fel fi,OF JERSEY CITY, NEW JERSEY, A. CORPORATION OF- NEW JERSEY.

ALTERNATING-CURBENT MAGNET.

Specification of Letters Patent.

Patented Jan. 4, 1916.

ication filed. March 550, 1812, Serial No. 685,112. Divided and thisapplication filed July 31,

1913. Serial No. 782,164. Y

. cnt magnets, and although i ted for general use, it is more adaptedfor use in conjunction aperatus such as is used in a electric elevators.

t is a division of my coication for a patent on alterbrake magnets,Serial No. d March 20, 3.912.

objects of my invention is to lo and cheap alternating current o lotwhich is of highly efiicie t constru and which involves a minimum amount()1 machine work.

Another object of my invention is to provide a simple id practical meansfor keeping the parts lubricated in a manner whereby all wear and. noiseis practically eliminoted ml the heat generated therein greatly reducer.

Other objects will appear hereinafter, the novel combinations orelements being pointod out in the appended claims,

ting to the drawings, Figure 1 is a view of the magnet and other 2 is adetail sectional view of upper part of the nnwnet showing an improved ml-hcd. of guiding and lubricat iug" net core, 3 is a view in partmodified form'of magnet.

' cc characters denote similar provide or pot 1, contains an electroinn.v 3* connected to the mechanism to erated, as for example a brake lever"not comprises a field member built up o la)" nto as is usual in theconstruction alternating current magnets, the assembled laminae to igheld in posi- 6y of end plates i and bolts, 3 and, 6. This field memberis i1l'\i in p tion inside of the pot I rods 7 which pass through as iand can in bosses cast in I lamina are stamped out of sheet iron and inform are substantially rectangular with a pole piece 9 extendingupwardly'at the lower end and an opening at the upper end to receive acore 10. The core is also of laminated construction, comprising a numberof stampings 10 having stays or end plates 11 preferably made of bronze;the laminae and end plates 11, together with a core head 12 beingfastened together by suitable rivets 13. The head, 12 and the upper partof the core are surrounded by a'divided casing 14: formed by anextension of the field end plates 4: and the space therebetween isfilled with Babbitt metal 15, which is poured in in a molten state. Thelower end of the core may be tipped with some non-magnetic maform asingle solenoid in efiect. The wind ing is wound on spools which areheld in place in. thefield frame by means of the;

field pole 9, and the top and bottom sup ports 18 and 19, respectively,one or more wedges such as designated by the numeral 20 being driven inbetween the upper support 18 andthe top magnet spool, after the magnetspools have been assembled, and held in place by means of a set screw asshown. The core head 121s hollow and contains a bearing, to which ispivoted by means of a pin 21, a connecting link 22 provided with aflange 23 The'upper end oi. this link is in, this instance pivoted by apin 24 to the brake lever T he upper end of the pot 1 is provided with acover 25 which loosely fits the core liea' 12 and holds in place a feltwasher 26 which is in con tact with the head and which serves thepurpose of a stulling box therefor, excluding all dust and dirt from theinterior of the mag-- net. casing or pot. The pot is partially filledwith transformer oil which has free access to all parts of the magnetand its function is to keep all'parts thoroughly lubricated and to actas a cushion for the'solenoid core, while at the same time the oil actsas heat conveying medium for carrying the heat generated in the magnetto the pot where an incense it is radiated. As an additional means forinsuring that all parts of the core may be supplied with lubricatingoil, I sometimes provide a channel. in the Babbitt metal surrounding thecore (see Fig. 2), which contains a wick 27, one end of which dips intothe oil contained in the pot, while the other end is in contact with thecore.

The pot cover 25 carries a stiff coil spring 28, which is somewhatshorter in length than the distance between the cover and the flange 23upon the connecting link 22. This spring serves the purpose ofovercoming the residual magnetism of the core and magnet fieldafter themagnet winding is deenergized. The conductors 29 lead to the terminalsof the magnet winding and are incased in a conduit 30 secured capped onone end, is connected to the lower end of the pot and furnishes aconvenient means for filling and emptying the pot with oil whenevernecessary.

In the modification shown in Fig. 3, a circumferential groove '32isturned to receive a flange on the divided casing 38,. and the cover 25,flange and ,pot, are held together by means of tl'irough bolts threadedinto the pot; These bolts are not shown in the sectional view Fig. 3,since their presence would tend to confuse the drawing. Thisconstruction dispenses with the rods 7 of Fig. l, and in some respectsis preferable thereover. The flange 82 divides the pot into two sectionswhich are in communication with each other through the adjustable puppetvalve 3%. This valve is independently adjustable in both directions andis so arranged that it Will never close tightly but will merely restrictthe flow of oil from the lower section t5) the upper section when thecore is drawnklownwardly, and will control the flow of the oil in anopposite direction. This action tends to cushion and re tard the releaseof by the magnet core, such as the Wake, but permits of a rapidapplication thereof.

By the use of Babbittmetal for guiding the magnet core,

work. The amount of clearance or air gap 35 (see Fig. 2) between thelateral faces of the magnet core and the magnet field, may be veryslight indeed, thereby improving the efficiency of the magnet, and, whenalternatingcurrent is used to excite the magnet, cut down the currentconsumption. The Babbitt metal forms a very efficient wearing surfacefor the core, and since ampleprovision is made for keeping the partslubricated, all wear of the magnet parts is practically eliminated. Itwill be observed that the oil contained in the magnet casing or pot 1,not only acts as a lubricating agent, but also as a means for dampeningthe vibrations set to the pot. A. riser 31,

the mechanism operated I provide a simple, cheap I and highly eiiiclentconstructlon involving a minimum amount of expensive machine up in themagnetic parts when the same are energized by an alternating current.The oil has free access to all parts of the magnet and forms a film overthe lateral faces and lower end of the core, which prevents an actualcontact of metal to metal. In alternatingcurrent magnets, the fluxconstantly varies, and when said current is of single phase themagnetism is reversed with each alternation of current. That is to say,for each alternation of current, the magnet is. dead and there is nopull upon the core. Now, since the spring 28 is tending to pull the corein an upward direction at all times when the circuit of the magnet isclosed, it follows that the core will tend to move away from the fieldpole 9, while the flux passes through zero, only to be pulled back incon tact again when the flux rises in value. ()rdinarily this actionsets up a violent hammering effect which not only tends to batter theend of the core out of shape and to make the action of the magnetextremely noisy, but also to reduce the elfective pull of the magnet.

The tendency of the residual magnetism to cause sticking of the magnetcore after the exciting current has been cut 0d, is practically overcomeby means of the air gap or break in the magnetic circuit found at thebdttom of the core and at the lateral faces oil the core where it passesthrough the field at the point 35, and this tendency'is reduced by thisconstruction to such an amount that if desired the German silver spacer16 upon the lower end of the core may be removed without preventing themetallic contacting.

While I have described my invention in conjunction with a single phasealternating current, the same may-be used to equal advantage withpolyphase or other currents of any nature.

Without limiting myself to the precise construction and arrangement ofparts herein described and illustrated,whfat I claim and desire to haveprotected by lletters Patent of the United, States is zl. Thecombination with an electro-responsive device, of a movable core, aguide for said core, and means for supplying oil to both ends of saidguide.

2. In an electro-responsive device, the combination with a solenoidmagnet, of a movable magnet core, a casing containing fluid surroundingsaid magnet and core, apartition dividing said easing into two parts,and a valve in said partition for regulating the passage of fluiddisplaced by said magnet core.

3. In an electro responsive device, the combination with a solenoidmagnet, of a movable magnet core, a. casing containing fluid surroundingsaid magnet and ,core,. .a

parts from actually danger of the core sticking, the oil iOS partitiondivic'iing said easing into two parts,

a valve in said partition for regulating the passage of fluid displacedby the magnet core, and means for limiting the movement 01 said valvetoward closed position.

4 In an electr0-respensive device, the combination With a solenoidmagnet of a. movable magnet core, a casing containing fluid surroundingsaid magnet and core, a horizontal partition dividing said easing intotwo parts, a, valve in said partition for regulating the passage offluid displaced by the magnet core; and means for limiting the movementof said valve toward closed position. 3i 1 5 In testimeny whereof, Ihave signed my name to this specification in the presence of twosubscribing Witnesses.

WILLIAM D..-LUTZ. Witnesses WALTER C. STRANG, ERNEST L. GALE, J r.,

